Synthesis of an advanced precursor of Rivastigmine: Cinchona -derived quaternary ammonium salts as organocatalysts for stereoselective imine reductions
作者:Andrea Genoni、Maurizio Benaglia、Emanuele Mattiolo、Sergio Rossi、Laura Raimondi、Pedro C. Barrulas、Anthony J. Burke
DOI:10.1016/j.tetlet.2015.08.086
日期:2015.10
stoichiometric reducing agent in the presence of catalytic amounts of a Lewis base, specifically a Cinchona derivative. For the first time, a novel class of derivatives was studied, featuring a picolinamide unit bound to the alkaloid scaffold, further functionalized as quaternary ammonium salt at the quinuclidine ring. Excellent yields and from good to high enantioselectivities (up to 92% ee) were
在催化量的路易斯碱,特别是金鸡纳衍生物的存在下,使用三氯硅烷作为化学计量的还原剂,已经成功实现了对酮亚胺的对映选择性还原。首次研究了一类新的衍生物,其特征在于与生物碱骨架结合的吡啶甲酰胺单元,在奎宁环上进一步被官能化为季铵盐。酮亚胺的还原获得了优异的收率,并且具有良好的对映选择性(高达92%ee)。新型催化剂已成功用于重磅炸药药物Rivastigmine的对映体纯的高级前体的合成中。